I put a block of dry ice in my coolers for car shows... I wrap it in foil to help slow down the melting, then put regular ice around it...
As the regular ice melts, it refreezes when it hits the block of dry ice... The cans get frozen into the ice for a day or so at the bottom, just keep restocking the cooler with more pop and ice as the days go by...
Then by Sunday the stuff on the bottom of the cooler will have melted enough to get the drinks on the bottom out....